Open AccessLow-frequency Flux Density Measurements and Pulsars with GHz-peaked Spectra
Author(s) -
J. Kijak,
Rahul Basu,
Wojciech Lewandowski,
Karolina Rożko
Publication year - 2021
Publication title -
astrophysical journal/the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.3847/1538-4357/ac3082
Subject(s) - pulsar , physics , giant metrewave radio telescope , astrophysics , supernova , interstellar medium , flux (metallurgy) , spectral line , astronomy , absorption (acoustics) , supernova remnant , radio spectrum , radio telescope , green bank telescope , galaxy , optics , radio galaxy , materials science , metallurgy
We have estimated flux densities of several pulsars from radio interferometric observations mainly at 325 MHz using the Giant Metrewave Radio Telescope. The new observations allowed us to update the spectral nature of the observed pulsars, and in six sources we identified relatively high frequency turnovers, which can be classified as new GHz-peaked spectrum (GPS) pulsars. For such objects the turnover in the spectrum is most likely caused by absorption in the immediate vicinity of the pulsar (or in the interstellar medium). We modeled the turnover spectra using the thermal free–free absorption model and the physical parameters obtained from the fits enabled us to identify the environments that could potentially be responsible for the observed absorption, such as pulsar wind nebulae, supernova remnant nebulae or H ii regions. The discovery of 6 new GPS pulsars brings the total number of such objects to 33 and we discuss the properties of the entire sample.